1. Field of the Invention
The present invention relates to a purification column in which fluid is purified by flow through a purifying component.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Purification columns are commonly used to purify fluids (gases or liquids) by passing the fluid through the column, contaminants or other unwanted parts of the fluid being extracted from the fluid by a purifying component, such as an absorbent, adsorbent, filter etc., contained in the column. For example, purification columns can be used as: compressed air and gas dryers, gas generators (e.g. generation of N2 by removal of O2 and CO2 from air), dust filters, refrigerant filters, vacuum pump filters, oil mist filters, etc.
Some purifying components can be re-generated in-situ. For example desiccants, such as activated alumina and molecular sieve materials used to remove moisture from compressed air and gas, may be re-generated using pressure swing technology, vacuum technology and/or heat regenerative technology. On the other hand, if the purifying component cannot be re-conditioned in-situ it may have to be replaced at regular intervals. For example, when activated carbon is used to remove hydrocarbon contamination from compressed air or gas, the carbon is generally replaced once spent.
Smaller purification columns are conventionally manufactured as two-piece moulded or cast constructions consisting of firstly, a top head manifold which provides a locator for a purifying component and inlet and outlet ports, and a lower filter bowl containing the purifying component, both parts being provided with male and female machined connections to enable them to be joined together as a pressure-containing sealed unit.
To manufacture a full range of cast component columns with varying pipe connections and flow capacities, can be costly due to the large number of moulding tools necessary to make the parts. In particular, individual top head manifolds may be connected to filter bowls of varying length, each requiring a separate moulding tool. Further, post-moulding, mating parts have to be accurately machined to enable them to be fastened together and to provide the purifying component locator.
The conventional method of manufacturing purification columns becomes particularly problematic when a plurality of similar columns are close-coupled together into a single purification system as few manufacturing cost-savings can be realised despite the increased number of columns.